Drive mechanism for centrifugal buckets



W. C. VOLK DRIVE MECHANISM FOR CENTRIFUGAL BUCKETAS Feb. 27, 1934.

Filed Oct. 6, 1931 Patented Feb. 27, 1934 'PATENT OFFICE DRIVE MECHANISMFon cEN'rmFUGAL BUcxE'rs Walter C.

Volk, Rome, N.

Y., assigner to Skenandoa Rayon Corporation, Utica, N. Y., a Acorporation of Delaware Application October 6,

9 Claims.

This invention relates to the manufacture of articial silk, and moreparticularly to a new and improved driving mechanism for centrifugalbuckets, or pots as they are sometimes called.

In the manufacture of artificial silk such centrifugal buckets are usedin spinning the silk according to the centrifugal or bucket-spinningmethod, and also in centrifugal washing, drying o'r other-treatment ofthe spun yarn.

10 Difficulty has been encountered with the'mechanisms heretoforeproposed for connecting these buckets to their drive shafts. Eachcentrifugal bucket is ordinarily arranged to; be rotated in a horizontalplane, and to this end is provided with its own vertical drive shaft,rotated at high speed mechanically or by an electric motor. When thespinning or other operation is completed the centrifugal bucket must bestopped and removed from the shaft and its contents-ordinarily a yarncake-*doied as by turning the bucket upside down. The bucket is thenreplaced upon the shaft and the operation recommenced.

It has been suggested to employ a straightsided tapered (i. e. conical)adapter upon the drive shaft, fitting into a complementary taperedbushing forming part of the base of the bucket. It has also beensuggested to employ a parallelsided, so-called "mushroom type ofadapter, t-

ting into a parallel-walled bushing embedded in 80 the base of thebucket, and driving by friction due to the weight of the bucket restingon a bottom flange or mushroom. These and similar proposals have beenfound unsatisfactory when attempted to be used in actual practice.

A conical adapter and bushing have been found to stick excessively sothat the bucket frequently cannot be removed for the purpose of dofngits contents. Hammering or the like must then be resorted to, withconsequent frequent breakage 40 of the bucket or the shaft, or bending.or injury of various parts of ,the mechanism. Also, thisstraight-tapered or conical form has the disadvantage that if the bucketstarts to rise, due to the bushing lifting on the adapter, there is a`tendency for the entire'bucket and its contents to be thrown upward andtofly off, with the likelihood of injury to the workmen and damage tothe plant. Of course it is understood that these centrifugal buckets arerotated at very high speed,

'50 and the danger if a bucket flies from the drive The mushroom typeofdrive mechanism is not i i satisfactory because the slippage is toogreat, and

1931. Serial N0. 567,209

the efficiency is consequently low. Also, ylubrica tion of the adapter.or bushing is usually required at dofng time, and this tends to increasethe slippage.

An object of the present invention is to provide a new and improveddrive mechanism for centrifugal buckets, and particularly to providesuch a drive mechanismvwhich will eliminate the disadvantages inherentin other. types of drive mechanism, including those mentioned above,while securing their advantages.

A further object of the invention is to provide a drive mechanism of theso-called semi-positive type, in which substantial slippage between thedrive shaft and the bucket or pot is permitted during starting andstopping, so as not to overload the motor or other driving means, but inwhich slippage is vreduced to a minimum while the bucket is in operationat speed, thereby providing greater eiiiciency.

A further object of the invention is to provide such a driving mechanismin which stieking of the separable drive members is prevented when thebucket or pot is to be removed for doing of its contents, and in whichthe necessity for lubrication is reduced to a minimum or eliminated. l

Another object of the invention is to provide lsuch a drive mechanismwherein risk of the bucket being thrown upward and flying oil' the driveshaft during operation is substantially eliminated,A with consequentreduction of danger to employees and risk of injury to the plant.

Still another object of the invention is to provide a drive mechanism inwhich interchangeability. of the buckets on the adapters fixed todifferent drive shafts is accomplished, even after substantial wear hasoccurred;i. e. in which the fit of the drive members is not affected,nor their interchangeability impaired, by wear. In this way, any bucket(with its embedded bushing) may be applied to the adapter on any driv'eshaft, even though wear may have occurred, and the eiiiciency ofoperation will not be diminished.

Other and further objects of the invention will appear from thefollowing description.

To accomplish the foregoing and other objects, I have invented the drivemechanism, or bucket assembly, which forms. the subject matter of thepresent application for patent, all as particularly pointed out anddistinctly claimedin A the appended claims, and of which I shall nowdescribe what is at present my preferred embodiment in greater detail inconnection with the accompanying. drawing, in which:

adapter is substantially cylindrical, the spindle Fig. 1 is a verticalsectional View through a centrifugal bucket with its bushing, anadapterv and shaft, according to an embodiment of the invention;

Fig. 2 is a horizontal sectional view on line 2--2 of Fig. 1;

Fig. 3 is a detail of the adapter and shaft of Fig. 1; and

Fig. l is a Vertical section through the bushing shown in Fig. 1.

Referring to Fig. 1, reference character 10 designates a tapered driveshaft, which may be the shaft of a suitable electric motor, for example.An adapter 11 is mounted on the shaft, to which it may be secured by adrive fit, for example, the shaft having a Morse or International taper.The outer surface 11a of the adapter 11, between the points marked 1lband llc (Figs. 1 and 3) is curved. In the instance illustrated, thecurve is the arc of a circle of radius designated X (Fig. 3). Below thepoint marked 11C, down to 11d, the outer surface of the adapter issubstantially cylindrical. Between points 11b and llc the adapterillustrated in Fig. 1 has the shape of a hollow truncated circularspindle. In that connection I use the term spindle in its geometricalsense to designate a solid which is generated by the revolution of thearc of a curved line about its chord. Such a spindle may be circular,elliptic, hyperbolic, parabolic, or curved according to other suitablelaw, depending upon the shape of its generating curve. As applied to anadapter of the character illustrated, I use the expressionspindle-shaped to include not only a hollow truncated spindle per se,but also a construction like that shown, in which the spindle surfaceper se merges into a cylindrical or other suitable surface at the baseof the adapter.

Fitting over and engaging the male drive mem ber or adapter 1'1 is afemale drive member, or hollow bushing, 12, of which the interiorsurface 12a has the same size, shape and curvature as the exteriorsurface 11a'l of the adapter 11. The

bushing 12 is embedded in the lower portion or.

i of the adapter between the lines marked 11b and 11c has the shape of atruncated circular spindle. Between the lines marked 11C and 11d thesurface merging gradually into the cylindrical one. The radius ofcurvature of the spindle surface is indicated at X, the center ofcurvature being located, as shown, on the line 11e, which radius ofcurvature, X, of the surface 12a is the same as that of the surface 11a,as indicated, and the center of curvature is located on the line 12e,which is slightly below the base-line, 126,.

of the bushing.

Lacasse I have found that in the case of a circular spindle-shapedadapter such as that illustrated, suitable dimensions are:

For the greatest diameter of the base 11/4"; for the outside diameter ofthe top HW for the distance between lines 11b and 11o 21%"; for thedistance between lines 11b and 11d 2&3 for the distance from line 11b tothe base 31/8; for the radius 0f curvature, marked X in Figs. 3 and 4,of the curved surface 11a of the adapter and the curved surface 12aI ofthe bushing 11"; and for the distance of the lines 11e and 12e,respectively, on which the centers'of curvature are located, below thelines 11c and 12e, gaf. The drawing is to scale.

Both the adapter and the bushing may suitably be made of brass orbronze. In certain cases it may be advantageous to make the adapter andbushing of dissimilar metals, preventing any tendency toward freezing,and permitting adjustment of the co-efiicient of friction to obtain thedesired amount of slip, while reducing or eliminating the necessity forlubrication.

I find by actual test and industrial use that the feature of a nearlyvertical facei. e. a subf stantially cylindrical surface-near the bottomof the male driving member (adapter, Fig. 3) where the spindle surfacemerges into the cylindrical one, in cooperation with a similar surfacenear the bottom of the female driven member (bushing, Fig. fi) reducesthe tendency for the bucket to lift from the shaft when rotated atspeed. The increased contact surface of the male and female members ofthe drive mechanism, due to their curvature, reduces slippage duringoperation at speed, while permitting necessary slippage duringacceleration and deceleration. And the curved or spindle-shaped" contourof the male and female drive members substantially eliminates sticking,so that the buckets can be readily removed from the shafts for doiing oftheir contents.

The construction herein specifically illustrated and described is atpresent my preferred embodiment of the invention, but it is to beunderstood that' the invention is not limited to that construction butcan be carried outl in other ways without departing from its spirit.

I claim:

l1. A semi-positive drive assembly for a centrifugal bucket, comprisinga drive shaft; a male drive member on said shaft having the form of ahollow truncated circular spindle merging, at its base, into asubstantially cylindrical surface and with the center of curvature ofthe truncated spindle surface lying in a plane below and parallel to theplane of the base of said truncated portion; a female drive memberhaving its interior surface conforming to the. exterior surface of saidmaleY member, and with the same radius and center of curvature as saidmale member; and a centrifugal bucket carried by said female drivemember.

2. In a centrifugal bucket driving mechanism of the semi-positive typefor use in the manufacture of artical silk yarn cakes by the centrifugalspinning method, the combination of a shaft driven by an electric motor,an adapter secured to said shaft and having an exterior surface convexlycurved axially of said adapter, a bushing fitting over and engaging saidadapter and having an interior surface concavely curved axially of saidbushing 'in conformity with the exterior surface of said adapter, and acentrifugal bucket carried by said bushing, said parts cooperating toMilk form a drive connection in which there is substantial slippagebetween shaft and bucket upon starting of the motor, to preventoverloading thereof, and in which said slippage is automaticallysubstantially eliminated when the parts have attained operating speed,the surfaces of said adapter and bushing further cooperating to preventsticking of the separable parts of the drive mechanism when it isdesired to remove the bucket from the shaft for dofiing the spun yarncake from the bucket after operation thereof.

3. A semi-positive drive for a centrifugal bucket, comprising a pair ofdrive members of which one is la female member carried by the bucket,and the other is a driven male member, the exterior surface of said malemember and the interior surface of said female member each having theform of the surface of a segment of a spindle, of which the surface isgenerated by the revolution of a curved line about a chord coincidingwith the axis 'of rotation of said male and female drive members, saidmembers co--operat-` ing to form a drive connection in which therel issubstantial slippage when the driven member is started in rotation, andsaid slippage is automatically substantially eliminated when the partsattained operating speed, the surface of said drive members furthercooperating to prevent sticking thereof When it is desired 4to separatethem after operation.

4. A drive mechanism for a centrifugal spinning bucket, comprising maleand female torquetransmitting members adapted to transmit rotation bymutual frictional engagement alone subject to mutual rotative slippageat desired times in the operation of the spinning bucket, said male andfemale members having surfaces which are co-axially engageable for saidfrictional torque transmission in a surface comprising that generated bythe revolution, about the driving axis of said members, of a curved lineco-planar with saidv axis.

5. A drive mechanism for a centrifugal spinning bucket, comprising amale member having an exterior torque-transmitting surface of revolutionwhich comprises a surface of revolution, about the driving axis, that isconvexly curved axially of said member, and a co-operating female memberhaving an interior surface of conforming configuration with the saidcurved surface of the male member, said members 'being thereby adaptedfor transmission of rotation by mutual frictional engagement alone,subject to mutual rotative slippage at times of substantial speed changein the operation of the centrifugal spinning bucket. l

6. The drive mechanism of claim 5 in which the surface of the malemember includes, at its end toward which the female member is urged bythe friction-producing engagement of the members, a cylindrical surfaceinto which the said convexly curved surface is merged.

7. In a centrifugal spinning bucket driving mechanism for themanufacture of artificial silk, in combination, a drive shaft, anadapter on said shaft having an exterior surface generated by therevolution, about the driving axis o'f the shaft, of a curved lineco-planar with the said axis, a bushing fitting over and engaging saidadapter and having a curved interior surface conforming to the exteriorsurface of said adapter, and a centrifugal spinning bucket carried bysaid bushing, said adapter and bushing co-operating to provide asemi-positive frictional drive connection susceptible of rotativeslippage at desired times and capable of supporting the bucket againstdisplacement transversely of its axis of rotation when the parts are indriving relation, and said bushing and adapter being freely separablefor removal of the spinning bucket for dofling operation or the like.

8. A centrifugal bucket assembly of the semipositive drive typecomprising a shaft, a centrifugal spinning bucket, and drivingconnections intermediate said bucket and shaft, said driving connectionsincluding a male adapter member having an exterior surface convexlycurved axially of said member, and a female bushing member engaging saidadaptermember and having an interior surface concavely curved ningbucket, and driving connections intermediate said shaft and said bucketadapted to provide a frictional torque-transmitting drive of said bucketfrom said shaft subject to rotative slippage at desiredtimes in theoperation of said bucket, and constructed for removal of the bucket.

from the shaft in dofling operation or the like, said drivingconnections comprising a driving member rotated by the shaft and havinga driving surface generated by the revolution, about the driving axis ofthe member, of a curved line co-planar with the said axis, and a drivenmember connected to the bucket for effecting rotation thereof and shapedto engage the driving member in conforming relation with the said curveddriving surface of the same.

WALTER C. VOLK.

oEgTIFtcATE or coRREcfuoN.

Patent No. 1,948,834. February 27, 1934.

WALTER o. vom.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as lollows: Page 3,line 27, claim 3, before "attained" insert have; and that the saidLetters Patent should be read with this correction therein that the samemay conform to the record of the case in the Potent Office. f

Signed and'sealed this 20th day' of March, A. D. i934.

E. M. Hopkins (geel)` Acting Commissioner of Patents..

